从嵌入式OSGi框架使用Log4j2

Question

我们正在使用ApacheFelix（版本4.4.1）作为嵌入式OSGi框架。提供该框架的主要应用程序使用Log4j2（版本2.0.1）作为日志框架。存在对log4japi和log4jcore的依赖。当然，当主应用程序启动时，也会加载和配置Log4j2。主部件中触发的所有日志消息都正确写入已配置的Appender。

现在是重点。加载的所有bundle都应该能够使用与主应用程序相同的配置和日志上下文。我试图做的是提供所有Log4j2包（来自log4j2api和log4jcore），将它们作为org放入框架配置中。奥斯基。框架系统包装。额外的。但是，当加载包时，log4j2包不会像其他提供的包那样出现在接线包列表中，并且当包类尝试访问log4j2类时，将引发异常。

所有捆绑包都以相同的方式配置，并且具有对log4j2api和Log4j2核心的Log4j2依赖关系，并提供范围。当我查看舱单时。MF使用的Log4j2包在导入包部分中

所以我的问题是。

为什么以这种方式导出Log4j2包不起作用？我必须如何配置我的环境，以便在捆绑包和主应用程序中使用相同的LoggingContext？

以下是我在java代码中对OSGi框架的配置部分：

Map<String, String> temp = new HashMap<String, String>();
// setting parameter that the felix cache is new initialized on each
// start of the application
temp.put(org.osgi.framework.Constants.FRAMEWORK_STORAGE_CLEAN, "onFirstInit");
// setting the packages that are provided by the main system and can
// be used by the osgi bundles
temp.put(org.osgi.framework.Constants.FRAMEWORK_SYSTEMPACKAGES_EXTRA,
// have to export these explicitly as the automatic export does
// not work for this internal java packages
+ "com.sun.org.apache.xerces.internal.dom,"
+ "com.sun.org.apache.xerces.internal.jaxp,"
+ "com.sun.org.apache.xerces.internal.util,"
// export the looging packages
+ "org.apache.log4j," + "org.apache.logging.log4j," +   "org.apache.logging.log4j.message,"
+ "org.apache.logging.log4j.simple," + "org.apache.logging.log4j.spi,"
+ "org.apache.logging.log4j.status," + "org.apache.logging.log4j.util,"
+ "org.apache.logging.log4j.impl," + "org.apache.logging.log4j.appender,"
+ "org.apache.logging.log4j.appender.db," + "org.apache.logging.log4j.appender.db.jdbc,"
+ "org.apache.logging.log4j.appender.db.jpa," + "org.apache.logging.log4j.appender.db.jpa.converter,"
+ "org.apache.logging.log4j.appender.jms," + "org.apache.logging.log4j.appender.rewrite,"
+ "org.apache.logging.log4j.appender.rolling," + "org.apache.logging.log4j.appender.rolling.action,"
+ "org.apache.logging.log4j.appender.routing," + "org.apache.logging.log4j.async,"
+ "org.apache.logging.log4j.config," + "org.apache.logging.log4j.config.json,"
+ "org.apache.logging.log4j.config.plugins," + "org.apache.logging.log4j.config.plugins.osgi,"
+ "org.apache.logging.log4j.config.plugins.processor,"
+ "org.apache.logging.log4j.config.plugins.util," + "org.apache.logging.log4j.config.plugins.visitors,"
+ "org.apache.logging.log4j.config.status," + "org.apache.logging.log4j.config.xml,"
+ "org.apache.logging.log4j.config.yaml," + "org.apache.logging.log4j.filter,"
+ "org.apache.logging.log4j.impl," + "org.apache.logging.log4j.jackson,"
+ "org.apache.logging.log4j.jmx," + "org.apache.logging.log4j.layout,"
+ "org.apache.logging.log4j.lookup," + "org.apache.logging.log4j," + "org.apache.logging.log4j.net,"
+ "org.apache.logging.log4j.net.jms," + "org.apache.logging.log4j.net.server,"
+ "org.apache.logging.log4j.net.ssl," + "org.apache.logging.log4j.pattern,"
+ "org.apache.logging.log4j.selector," + "org.apache.logging.log4j.tools,"
+ "org.apache.logging.log4j.util," + "sun.misc," + "javax.jms," + "javax.mail,"
+ "javax.mail.internet," + "javax.mail.util," + "javax.persistence," + "javax.servlet,"
+ "com.sun.xml.internal.bind");
temp.put(FelixConstants.LOG_LEVEL_PROP, "4");
OSGI_CONFIG = Collections.unmodifiableMap(temp);

捆绑包中对log4j2 libs的依赖项定义如下：

<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-core</artifactId>
    <version>2.0.1</version>
    <scope>provided</scope>
</dependency>
<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-api</artifactId>
    <version>2.0.1</version>
    <scope>provided</scope>
</dependency>

Answer 1

我在OSGi（Eclipse）中有log4j工作正常。

正如@Fenris Ulth所提到的，您可以为包含log4j2的log4j核心创建一个片段。xml配置文件。对于log4j2version2.3，我发现在代码开始使用log4j记录消息之前，我必须激活log4japi包，否则就会出现这里描述的错误。我通过将其设置为低启动级别的自动启动来实现这一点。

Answer 2

我有log4j2在osgi工作在一个相对简单的配置。

您必须创建两个片段。

• 第一个片段应该有log4j-api作为宿主。它应该包含一个文件：META-INF/log4j-providers.properties（将其从log4j2-core中拉出来）
• 第二个片段应该有log4j-core作为宿主。它应该包含一个文件：log4j2.xml（或任何您想要的配置文件）

这只需要将log4japi和log4j核心jar文件放到plugins目录中（如果您使用equinox，则为p2）。我有以下链条运行良好：

共享日志（jcl-over-slf4j）-

注：slf4j版本1.7。7 log4j2版本2.1

Answer 3

我们找到了一个解决方案，它适用于2.0版。1.而不是在清单的导入包部分中设置所需的log4j包。MF我们已将它们添加到DynamicImport包定义中。之后，在需要时动态连接类，所有OSGi包都可以使用相同的LoggerContext。